By Dr Edward Nazareth
May 31: With the easing of lockdown measures leading to opening of several business establishments, public transport and places of worship, the danger of acquiring COVID 19 infection is high. People have to learn to protect themselves from the deadly virus and also take care that they do not spread infection and harm someone vulnerable. When a person has the symptoms of the infection now, he or she is isolated from others and the spread of infection is avoided. However, there are two other categories that are of real concern -asymptomatic carriers and people in pre-symptomatic period after being infected with the COVID 19 virus.
(Meantime, it has to be remembered that several new issues are surfacing regarding COVID 19 infections and we may have to keep updating ourselves.)
Asymptomatic: The real concern
The numbers of positive cases of COVID 19 virus infection have alarmingly increased in Karnataka after the return of people from neighbouring states. They were quarantined and tested and found infected. Most of these people were tested before they boarded the transport, their thermal screening was negative and they were not sick. Almost all of them have not developed any symptoms of viral infection even in quarantine facility. The infection was detected only because their throat swabs were subjected to tests. These are ‘asymptomatic’ people. Their immune system produces antibodies and eliminates the viruses after a definitive period (believed to be 14 days). Once the viruses are eliminated they do not spread the viruses to others. Their body has antibodies which protects them from getting infected by the same virus again for certain time.(Again, it is not sure how long the antibodies protect them from re-infection).
In simple terms, asymptomatic means a person who doesn’t show any symptoms of the disease. So, a person could be infected with COVID-19 but may not show any symptoms of the disease such as cough, cold, fever and others. It is a worry because a patient who has COVID-19 and is asymptomatic could unknowingly spread the infection, because even though there are no visible symptoms, the person is still infectious and has the potential to spread the virus to others. If the people who had returned from neighbouring states were freely allowed to go to their families here, they would have spread the infection to many people. As per a study from China, 44% of those who had contracted the COVID 19 disease had caught it from an asymptomatic person.
Asymptomatic people are the biggest risk of spreading COVID 19 infection now. As the persons are asymptomatic, they do not qualify for immediate testing and may slip detection till the scope and reach of coronavirus testing are widened. This is humanly impossible in a country like ours.
The asymptomatic people are also known as "silent spreaders" who unknowingly infect others and they have sparked concerns. “Among the total coronavirus tests conducted so far in India, 69% were asymptomatic and 31% were symptomatic. Which means for one positive patient when we initiated contact tracing, on average we found two asymptomatic patients," ICMR’s head of epidemiology and communicable diseases Raman Gangakhedkar said recently.
The unfortunate people who develop the symptoms of the infection are the real patients of COVID 19 infection. The time taken for developing the symptoms is known as incubation period. This period is also known as pre-symptomatic period. Symptoms may develop 2 days to 2 weeks following exposure to the virus. The average incubation period is around 5.1 days and 97.5% of individuals developed symptoms within 11.5 days of infection. Many of these people can spread the infection 2 to 3 days before they develop the symptoms. It is believed that before the onset of symptoms they have greater viral load and can be highly infectious. Identification of such people again is a big challenge.
Not only cough or sneeze, even normal breath
Initially it was informed that the coronavirus spread only through a person’s cough or sneeze. Now it is believed that virus also spreads through normal exhalation that carries tiny droplets containing viruses. A regular breath may spread the viruses several feet.
The viruses that are fallen can remain infective on the surfaces, such as a doorknob or a grocery cart handle, a seat in a public transport, on the floor or on furniture in a place of worship.
It is not certain how long COVID-19 virus survives on surfaces, but it seems to behave like other coronaviruses. Studies suggest that coronaviruses may persist on surfaces for a few hours or up to several days. This may vary under different conditions (e.g. type of surface, temperature or humidity of the environment). For example, on wood, the virus may remain active for 4 days, on cardboard up to 24 hours and up to 2-3 days on plastic and stainless-steel surfaces.
This information is important as the places of worship will be open soon. If an asymptomatic person has spent time on a kneeler for few minutes, he can deposit the viruses as he prays. Singing and praying loudly can deposit more viruses and on a larger surface. Unless the area and the furniture are disinfected, the people who pray at the same place for the next 4 days can get infected by the COVID 19 viruses which are highly infectious. This is same for any other common places like public transport, shopping malls, gymnasiums or cinema halls.
Vulnerable are to be protected
While researchers are still trying to figure out how COVID-19 affects different people, elderly persons and persons with pre-existing medical conditions (such as asthma, chronic bronchitis, certain cardiac diseases, improperly controlled diabetes and other immune deficiency status) appear to develop serious illness more often than others. Pregnant ladies and children below the age of 10 also are at higher risk of developing disease if they contact the viruses.
It is not enough if such people are totally confined to home, all at that home have to be careful that they do not get infected and transmit it to these vulnerable as asymptomatic spreaders. The vulnerable people have to take care and they have to be protected till the severity of the infection subsides.
Basics of self protection
Though several issues related to infection, disease and medication have changed, the basic principles of protection from COVID 19 infection have not changed.
Washing hands often
• Washing hands with soap and water for at least 20 seconds after visiting a public place like market, mall or place of worship.
• If soap and water are not readily available, a hand sanitizer that contains at least 60% alcohol may be used. All the surfaces of the hands are to be rubbed together with sanitizer until they feel dry.
• Avoid touching the eyes, nose, and mouth with unwashed hands.
Avoiding close contact
Always remember to maintain at least one meter (3 feet) distance between the persons in public places. The person next to you can be an asymptomatic spreader or may be in the pre-symptomatic stage. Protect yourself by maintaining social distance. This is especially important if more time is spent with such people such as at meetings or places of worship.
Always using a face mask
Cover your mouth and nose with a proper mask when around others. This is important because you could spread COVID-19 to others even if you do not feel sick.
Disinfecting the office spaces
The office spaces should be cleaned every evening after office hours or early in the morning before the rooms are occupied. After routine cleaning, the areas should be mopped with a disinfectant such as 1% sodium hypochlorite solution. Commercially available bleaching powder (70% chlorine) can be used to prepare the hypochlorite solution. About 7 grams of bleaching powder per one liter of water may be used to prepare the solution.(If liquid bleach is used, the preparation of solution depends on the percentage of available chlorine. 3.5% liquid bleach 1 part bleach to 2.5 parts water; 5% liquid bleach 1 part bleach to 4 parts water.)
High contact surfaces such elevator buttons, handrails / handles and call buttons, public counters, intercom systems, equipment like telephone, printers/scanners, and other office machines, frequently touched areas like table tops, chair handles, keyboards, mouse, mouse pads should be cleaned twice daily by mopping with a linen/ absorbable cloth soaked in 1% sodium hypochlorite. Solution containing 70% alcohol can be used to clean the metallic surfaces like door handles, security locks, keys etc.
Using the public transport
The transport hubs are regarded as infection hotspots, with virus transmission rates up to six times higher for those using public transport systems. Planes, trains and buses (and the stations and airports) can transmit droplet-spread diseases such as COVID 19. Those commuters who take long journeys or use busy interchange stations/airports are at high risk as they come into contact with more shared surfaces and people.
The security checks are thought to be the highest risk areas in airports. The plastic luggage trays at security checks which are hardly cleaned can spread the virus to many.
Hand rails on escalators, arm rest on waiting area, seats and the constant passing of tickets and passports to airline and security staff is also likely to present risk. The door handles, side handles, grab handles, seats, windows, partitions etc. in buses or trains can spread the infection to many. It is not always easy to travel without touching these.
Only way to avoid infection is to travel during non-peak hours and to be aware that the viruses might be spread on all the available surfaces. Most of the public transport operators are following the norms of social distancing and hygiene.
However the traveler has to take extra precautions:
• Always try to stay at least one meter away from other passengers.
• Good quality hand sanitizer (containing at least 60% alcohol) should be carried with and should be used as soon as boarding the public transport.
• A face mask and goggles has to be used during the journey. (If traveling by flight, it may be ideal to use a good quality N 95 surgical mask throughout the journey.)
• Maximum care has to be taken not to touch the face.
If journey is long, frequent use of hand sanitizer is ideal. If facilities are available (such as in trains) washing the hands using soap is better than using hand sanitizers